Energy 2: Acetyl Coenzyme A, Mitochondrial, Oxygen

Question 1

What does TCA stand for?

Answer 1

Tricarboxylic acid cycle

Question 2

When and where does aerobic respiration happen?

Answer 2

In the presence of oxygen, in mitochondria

Question 3

What is the output of the TCA cycle?

Answer 3

8 NADH
2 FADH2
2 GTP
6 CO2

Question 4

Where does the TCA cycle take place?

Answer 4

In the mitochondrial matrix

Question 5

What is pyruvate converted to in the TCA cycle?

Answer 5

Acetyl coA

Question 6

What does acetyl CoA react with to form citrate?

Answer 6

Oxaloacetic acid

Question 7

What regulates entry into the TCA cycle?

Answer 7

Formation of acetyl coA from pyruvate is irreversible. Commits the glucose carbon skeleton to either oxidation to CO2 or fatty acid synthesis

Question 8

What is the enzyme involved in regulation of entry into the TCA cycle?

Answer 8

Pyruvate dehydrogenase

Question 9

What is pyruvate dehydrogenase inhibited by?

Answer 9

Inhibited by NADH, ATP and acetyl coA

Question 10

What other two enzymes are involved in regulation of the TCA cycle (not pyruvate dehydrogenase)?

Answer 10

Kinase and phosphatase

Question 11

In muscle, what is pyruvate hydrogenase phosphatase stimulated by?

Answer 11

Ca2+

Question 12

In the liver, how does adrenaline increase Ca2+?

Answer 12

Through the stimulation of alpha adrenergic receptors and IP3

Question 13

What does insulin stimulate in liver and adipose tissues?

Answer 13

Phosphatase which funnels glucose to fatty acid synthesis

Question 14

What is pyruvate dehydrogenase stimulated by?

Answer 14

ADP pyruvate

Question 15

What is citrate synthase inhibited by?

Answer 15

Citrate

Question 16

What is isocitrate dehydrogenase inhibited by?

Answer 16

NADH, ATP

Question 17

What is isocitrate dehydrogenase stimulated by?

Answer 17

ADP

Question 18

What is alpha-ketoglutarate dehydrogenase inhibited by?

Answer 18

NADH, ATP, succinyl CoA

Question 19

What is beri beri and where is it common?

Answer 19

A deficiency in thiamine (vitamin B1), common where rice is a staple

Question 20

What is beri beri characterised by?

Answer 20

Cardiac and neurological symptoms

Question 21

What is thymine a prosthetic group for?

Answer 21

Pyruvate and alpha-ketoglutarate dehydrogenase

Question 22

What happens to the NADH and the FADH2 produced in the TCA cycle?

Answer 22

They donate hydrogen atoms to complexes where the atom is split into proton and electrons

Question 23

What happens to the electrons produced by the breakdown of hydrogen in the mitochondria after the TCA cycle?

Answer 23

Transported through the cytochromes (final acceptor is oxygen which is then used to generate water)

Question 24

How many ATP molecules does NADH and FADH2 form in oxidative phosphorylation ?

Answer 24

NADH forms 3, FADH2 forms 2

Question 25

How many protons does NADH and FADH2 pump out in oxidative phosphorylation ?

Answer 25

10 for each NADH | 6 for each FADH2

Question 26

Give the steps in ATP synthesis

Answer 26

As electrons are passed down the ETC protons are pumped from the mitochondrial matrix into the intermembrane space, which forms an electrochemical gradient. The gradient is dissipated by the passage of protons through ATP synthase, which forms ATP

Question 27

How much (lots or not much) mitochondria is there in brown fat?

Answer 27

Lots

Question 28

Where is brown fat found in babies?

Answer 28

The shoulder/neck area

Question 29

What is brown fat used for?

Answer 29

To generate heat for as a newborn

Question 30

What protein do brown fat mitochondrial inner membranes contain?

Answer 30

Uncoupling protein 1 (UCP1)

Question 31

What does UCP1 do?

Answer 31

Diverts the flow of protons away from the generation of ATP and through to the generation of heat. (Proton gradient is dissipated but not in the same way)

Question 32

What are OXPHOS diseases?

Answer 32

Common degenerative diseases

Question 33

What are OXPHOS diseases caused by?

Answer 33

Mutations in genes encoding ETC proteins

Question 34

What are the symptoms in OXPHOS diseases caused by and when do they appear?

Answer 34

Fatigue, epilepsy, dementia | Dependant on the mutation, symptoms may be evident near birth early to early adulthood

Question 35

What is congenital lactic acidosis?

Answer 35

Can’t make ATP through ETC do have to do it through the conversion of pyruvate to lactate